Process of making cellulose nitro acetate



i arate processes.

" ing to the process nitrating acid mixture, for

ble effect of having combined two expensive Patented Aug. 11, 1931UNITED STATES PATENT OFFICE LUDWIG LOCK, OF DORMAGEN-ON-THE-RHINE,GERMANY, ASSIGNOR TO I. G. F-ABBENP INDUSTRIE AI KTIENGESELLSGHAF'I', OFFRANKFORT-ON-THE-MAIN, GER-MARY, A

CORPORATION" OF GERMANY PROCESS OF MAKING CELLULOSE NITRO ACETATE NoDrawing. Application filed September 12, 1929, Serial No. 392,257, andin Germany September 19, 1929.

The present invention relates to a process of preparing cellulose nitroacetates.

The manufacture of cellulose nitro acetates has hitherto been carriedout in two sep- Thus, forexample, accordof the German Patent No.295,889, the bleached cellulose serving as the starting material ispreliminarily nitrated by a mild treatment with a weakly acting example,to a nitrogen content of 2%, freed from adhering acid, washed and dried,after which acetylation is effected in the second stage of the processby one of the known technical methods.

The present invention describes a new process of producing cellulosenitro acetates in one and the same process in a technically easy andsimple manner. sists in acetylating the cellulose at temperaturesbetween about and 100 C. by means of acetic acid and acetic anhydride inthe presence of a calculated amount of a salt of nitric acid with a weakinorganic or organicase, such as for example ammonium nitrate, zincnitrate, aniline nitrate and urea nitrate, with the addition of a smallamount, say about 0.21% calculated on the amount of the cellulose to beacidylated, of a free mineral acid, especially sulfuric acid. Thequantity of the salt of the nitric acid to be added to the reactionmixture depends on the desired nitrogen content of the cellulose nitroacetate to be prepared. Thus, there- 7 are obtainable cellulose nitroacetates w1th a nitrogen content of about 0.1 to 1.8%.

'In addition to the extraordinarily valuaseparate processes into asingle reaction, which is readily and securely carried out the new andtechnically equally important feature must be considered of being ableto predetermine in this manner the nitrogen conb tent of the ultimatecellulose nitroacetate.

The nitro acetates obtained in this manner are extraordinarily clear andviscous and b form a valuable material for the film industry, which isdistinguished among others from the products obtained from non-ni- Theprocess contrated cellulose acetate by duced water stretchability.

The invention is illustrated by the following examples, withoutbeinglimited thereto:

Example 1.One part by weight of cellulose is heated at 70 C. with 5parts by weight of acetic anhydride, 3 parts by weight of glacial aceticacid and 0.05 parts by weight of ammonium nitrate with the addition of0.003 parts by weight of sulfuric acid until atest portion is found tobe soluble in chloroform. The triacetate contains 0.6% of nitrogen(calculated on the cellulose). The resulting nitro acetate is thenhydrolized according to one of the known processes.

Ewample 2.O ne part by weight of cellulose is heated at 100 C. with 4parts by weight of acetic anhydride, 2 parts by weight of glacial aceticacid and 0.5 parts by weight of ammonium nitrate with the addition of0.004 parts by weight of sulfuric acid until a test portion is found tobe soluble in chloroform. The triacetate contains 1.5% of nitrogencalculated on the cellulose. It is then hydrolized according to one ofthe known processes. "1

E trample 3.-One part by weight of cellulose is heated at 80 C. with 3parts by weight of acetic anhydride, 3 parts by weight of glacial aceticacid and 0.1 part by weight of urea nitrate with the addition of 0.005parts by weight of sulfuric a considerably reacid until a test portionis foundto be soluble in chloroform.

The triacetate contains 0.8% of nitrogen, (calculated on the cellulose)it is then hydrolized according to one of the known processes.

I claim: 1. The process which comprises acet lating cellulose betweenabout 50 and 100 means of acetic acid and acetic anhydride in thepresence of a small amount of mineral acid and of a salt of nitric acidwith a weak ase. 11 2. The process which comprises acetylating cellulosebetween about 50 and 100 C. y means of acetic acid and acetic anhydridein t 'e presence of a small amount of sulfuric acid and of a salt ofnitric acid with a; weak base.

3. The process which comprises acetylating cellulose between about 50and 100 C. by means of acetic acid and acetic anhydride in the presenceof Oil-1% (calculated on the 5 amount of the cellulose) of sulfuric acidand of a salt of nitric acid with a weak base.

4. The process which comprises acetylating cellulose between about 50and 100 C. by means of acetic acid and acetic anhydride in the presenceof 0.24% (calculated on the amount of the cellulose) of sulfuric acidand of urea nitrate.

In testimony whereof, I afiix m signature.

LUDWI LOCK.

